The present invention is directed to a composite soap article formed from a transparent or translucent molten matrix soap material that is poured to surround one or more solid soap inserts, said inserts formed from a higher melting point soap composition that is visibly differentiatible from the surrounding transparent matrix soap composition due to a difference in opacity and/or color. In a preferred embodiment, the insert soap composition differs from the surrounding soap composition only by water content and/or dye and/or pigment additionxe2x80x94the insert soap composition having less water than the surrounding soap composition in a preferred embodiment, making the insert composition more opaque and having a higher melting temperature than the surrounding transparent matrix soap composition.
Composite, decorative soaps, sometimes called mosaic soaps, are well known in the art as evidenced by the Inui et al. U.S. Pat. No. 4,504,433. These composite soaps are formed by placing one or more solid pieces of insert soap, in the form of a decoration, design, or written material, into a mold, holding the insert(s) in position within the mold and then pouring a solution of a melted transparent soap to fill the mold, thereby surrounding the insert(s). The transparent soap is generally poured into the mold to surround the inserts at temperatures in the range of about 60xc2x0 C. to about 75xc2x0 C. and the transparent soap then is cooled to solidify, thereby permanently holding the soap insert(s) in position.
The soap inserts, also known as icons, can be formed from various soap compositions, generally about 85% sodium stearate and 15% water, making an opaque soap, or can be formed from various other compositions such that the icons or inserts will be visibly distinguishable relative to the surrounding transparent matrix soap composition so that the icons or inserts are clearly visible within the composite bar of soap. It should be understood that the terms xe2x80x9cinsertxe2x80x9d and xe2x80x9ciconxe2x80x9d are used interchangeably herein, however, xe2x80x9ciconxe2x80x9d should not be understood to require the insert soap composition to be formed in any definite or predetermined shape or size. The insert or icon soap composition can be any predetermined or random shape or size.
These decorative soap bars are very appealing and attractive from a visual standpoint but have a number of drawbacks, some of which result from the substantially different soap compositions used for the icons or inserts as compared to the composition of the surrounding transparent soap material. During use, the higher dissolution rate of the clear soap results in an uneven wearing of the soap barxe2x80x94the matrix or clear soap dissolves in water about two to three times faster than icons made of regular sodium stearate-based, opaque soap. Further, during storage, often there is chemical migration from the clear matrix soap into the inserts at the insert/matrix interface, resulting in the softening of the inserts. In addition, although the decorative soap bars are normally wrapped in a protective polymeric film, the clear matrix soap loses weight at a higher rate than the surrounded soap inserts, thus distorting the appearance of the decorative bar of soap.
Another common problem with such decorative soaps is from dye xe2x80x9cbleedingxe2x80x9d which results from dye migration from the soap inserts into the surrounding transparent matrix soap composition. Further, recycling of any defective or unsold soap bars is virtually impossible with extant decorative bar soaps due to the substantially different compositions for the insert and matrix soaps.
Mottola U.S. Pat. No. 5,217,639 discloses a decorative soap bar that includes an opaque portion and a transparent portionxe2x80x94both portions adjoining each other only along a single curvilinear shaped surfacexe2x80x94wherein the opaque and transparent soap compositions differ only by including a solid pigment in the opaque composition. However, the melting points of both soap compositions are the same so that one composition melts partially when contacted with the other soap composition during manufacture so that detailed icons or inserts are impossible.
In brief, the present invention is directed to a decorative bar of soap including one or more internal soap inserts, in any desired shape, surrounded and completely encased by a transparent or translucent matrix soap composition, wherein the surrounding matrix soap composition has a lower melting point than the icon or insert soap composition.
In accordance with a preferred embodiment of the present invention, the soap composition used to form the icons or inserts can be the same as that for the surrounding transparent matrix soap composition with the exception that the icon or insert soap composition must, in any manner, be made to be visually distinguishable from the surrounding or matrix soap composition, e.g., the insert is made less translucent or less transparent than the surrounding composition by virtue of having less water; having an increased concentration of insoluble soap; having an increase in the carbon length of the insoluble soap; having higher boiling solvent(s); containing a dye or pigment; and/or having higher melting point surfactant(s), but otherwise may contain the same components as the surrounding matrix soap composition. By including less water in the icon or insert soap composition, the icons or inserts may become readily visually distinguishable from the surrounding matrix soap composition, in being more opaque than the surrounding matrix soap composition, and the icons or inserts have a higher melting point, being at least 3xc2x0 C. higher, than the surrounding matrix soap composition when formed with the components described hereinafter. In accordance with another important feature of the present invention, the increase in melting point of the icon soap composition can be affected by an expedient selected from the group consisting of: (1) a lower amount of water; (2) an increase in the insoluble soap content; (3) an increase in the carbon chain length of the insoluble soap; (4) solvents having a higher boiling point; and/or (5) different surfactant(s) causing a higher boiling point in the icon soap composition.
The above and other aspects and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments, taken in conjunction with the drawing.